1. Add synaptics_dsx_i2c.c and synaptics_dsx_spi.c as bus abstraction layer.
2. Move all synaptics related files to new folder under /kernel/drivers/input/touchscreen/synaptics_dsx/
3. Introduce platform driver and platform device to synaptics_dsx_core.c
4. Fix OMAP SPI kernel issue while enable CONFIG_SPI_OMAP24XX=y in panda_defconfig